Battery Configuration - Toro 88620 Service Manual

Features Managed by Product

Battery Configuration

Amp Hours and Voltage
Battery Configuration: Watt Hours
Determining Watt Hours
Theory of Operation: Service and Repairs
Features managed by the product include tool operations and power usage
control. The BMS does not tell the tool what to do and it does not dictate how
much power is being used, the tool does.
When thinking about battery configuration, the 3 key terms are: voltage, amp
hours, and watt hours. Individual cylindrical cells are configured in parallel and
series to form a battery pack.
Voltage in volts (V), is a measure of electrical potential. To build voltage in a cell
pack, individual battery cells must be connected in a series. For example, the
voltage of each battery is 3.7 volts with 3 batteries in the series. The total voltage
is 3.7 volts (per battery) times 3 batteries, which equals 11.1 V.
Amperage, in amps (A), is a measure of instantaneous electrical current.
Batteries are often rated in amp hours (Ah). For example, 2.5 amp hour battery
can discharge 2.5 amps continuously for 1 hour. The amp hour rating is the size
(or capacity) of the products energy source- a 2.5 Ah battery will do half of the
work of a 5 Ah battery in the same voltage family. In order to build capacity, more
strings of cells must be added in parallel. The amp hours of each individual
battery is 2.5 and there are 4 batteries in parallel resulting in a total of 10 Ah.
Watt hours is the measurement of work done by the tool. The electrical energy, in
watt hours (Wh), is a measurement of power over time that can be converted into
physical work. Both watt hours of the battery and the tool's watt hour capacity
are important information to know.
Watt hours is determined by multiplying amp hours by volts. Using an individual
battery cell that has 3.7 volts and 2.5 amp hours, means 3.7 volts in a series of 3
which results in a total voltage of 11.1 volts.
This indicates 4 cells in parallel, each cell equaling 2.5 amp hours resulting in 10
total amp hours for this configuration. To determine watt hours, take the total
voltage of 11.1 and multiply by the total amp hours of 10, resulting 111 watt hours
for this battery configuration example.
Page 4–6 60v Battery Service Manual
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